Bronchospasm: Not always the cause for tight bag

Abstract

Dear Editor, A 2-year-old child with history of difficulty to void urine was diagnosed with hypospadiasis and was scheduled for urethroplasty. The child weighed 14 kgs and had no comorbid illness. There was no history suggestive of recent respiratory tract infection and the child was active and playful. Premedication was done with 200 μg of transmucosal fentanyl citrate lollipop. On shifting to the operating room, standard monitors were connected. Anesthesia was induced with sevoflurane in 100% oxygen using Jackson-Rees circuit. Once anesthesia was induced, intravenous (IV) access was secured with 22-G canula. Anesthestic depth was deepened with IV propofol 10 mg and neuromuscular blockade achieved with IV vecuronium 1.5 mg. Ventilation was assisted with oxygen and sevoflurane 2% for 3 minutes. Trachea was intubated with size 4.5-mm uncuffed oral endotracheal tube (Sterimed, India). Immediately on intubation, the feel of the reservoir bag was too tight. Attempts to auscultate the lung fields revealed only faint/absent sounds. There were no crepitations or wheeze. Possibility of endobronchial intubation was ruled out by auscultation of the lung fields. Severe bronchospasm was suspected. Anesthetic depth was increased with IV bolus of propofol 10 mg and IV ketamine 10 mg. Four salbutamol puffs were delivered through the endotracheal tube. Sevoflurane concentration was increased to 3% in 100% oxygen. As all these manoeuvres did not make any difference and peak airway pressures were reaching beyond 50 cm H2O to deliver even 50 ml of tidal volume, possibility of endotracheal tube block was suspected. A 8-Fr suction catheter was passed through the endotracheal tube revealed no tube obstruction. While attempting to reconnect the endotracheal tube to the connector it was noticed that the tube end of the connector had a pinpoint opening [Figure 1]. The connector was replaced with another normal one which solved all the problems. The procedure was uneventful and neuromuscular blockade reversed and tracheal extubation done at the end of surgery.Figure 1: The abnormal constriction of the endotracheal tube connector compared with the normal oneInability to provide adequate ventilation in an intubated patient without excessive pressure being applied to the reservoir bag can be termed as a tight-bag situation.[1] In a tight-bag situation the peak airway pressures can increase beyond 25 cm H2O. Even though equipment malfunction or defects are quite common, they often go undetected leading to delay in correct diagnosis and proper management of the case.[2] The pinpoint constrictive defect of the connector of the endotracheal tube which was initially used in our patient could have significantly increased the resistance to airflow leading to a tight-bag situation. As evident from Poisiuele’s law, the resistance can increase by fourth power of radius of a tube. Poisiuele’s law R = 8nl/πr4 (n - Viscosity, l - Length). Tight-bag situation with inadequate ventilation is a night mare for any anesthesiologist. Going through a complete machine check including the breathing circuit before anesthetizing the patient and having a systematic protocol based approach to the tight-bag situation will help in early identification and rectification of the problem.